Braiding or stranding machine having a rotor yoke and transport device

ABSTRACT

A braiding or stranding machine for the braiding or the stranding of a strand shaped material  2  comprises a rotor yoke curved radially outward and rotatably around an axis of rotation, the two ends of which lie on or near the axis of rotation and the strand shaped material  2  is moved along the longitudinal direction thereof during operation of the braiding or stranding machine. The rotor yoke comprises a transport device  1  for the strand shaped material  2,  which is provided to contact the strand shaped material  2  on only one part of the longitudinal extension of the rotor yoke and to move at the contact surface with the strand shaped material  2  in the same direction as that of the strand shaped material  2.    
     According to the invention, the transport device  1  is adapted to contact the strand shaped material  2  only on a part of the longitudinal extension of the rotor yoke. 
     In this way, the contact surface between the transport device  1  and the strand shaped material  2,  and thus the extension of the transport device  1  itself, can be reduced, by which means the aerodynamic drag of the transport device  1  also decreases.

The entire content of the priority application DE 10 2013 010 960.2 is incorporated by reference into the present application.

The invention relates to a braiding or stranding machine for the braiding or for the stranding of strand shaped materials. The strand shaped material can be, for example, a metallic material such as a copper wire, a steel wire or an aluminum wire or a metallic conductor with various alloy components, or a non-metallic material such as a natural fiber or a synthetic fiber, wherein several strands of such a wire or of such a fiber are stranded together by twisting, i.e. processed into a braid. The strand shaped material can be also, for example, such a braid, wherein then several strands of such braid are twisted with each other, i.e. processed into a cord or a rope.

For simplicity, the invention will be described below with reference to a braiding machine. However, this is not a limitation. The invention can also be applied to a stranding machine.

In a braiding machine of the type considered herein, the braiding is performed by a rotating rotor, which has usually one or more radially outwardly curved rotor yokes, wherein two of their axial ends are supported on a single-part rotor shaft or on a multi-part rotor shaft and to rotate around the axis of rotation of the rotor. At least two strands of the strand shaped material (of the same or of a different type) are supplied to the rotor and passed over a rotor yoke, whereby a twisting of the strands is performed.

In this case, the strand shaped material is guided usually along the inner side of a rotor yoke, for example by passing it through several eyelets, which are fastened in certain intervals on this rotor yoke so that it does not slip off from the rotating rotor yoke. As the strand shaped material is thereby pressed by the centrifugal force against the inside of the rotor yoke, this is often provided with a friction reducing coating and/or a wear reducing coating or a lining, for example in the form of a sliding rail made of tungsten carbide.

The braid, which has prepared in the manner described above, is then discharged again from the rotor yoke.

Both the strand shaped material to be braided as well as the braids produced there from are provided on spools or wound up again on a spool of the braiding machine. In order to achieve different forms of twisting of the strand shaped material, the spool for the strand shaped material or the spool for the braid produced may be either resting or rotating with the same speed and in the same direction as the rotor. The spools may be arranged within the braiding machine, in particular between the axial ends of the rotor, or outside the braiding machine. By various suitable arrangements of the spools, a so-called single lay braiding machine, a double lay braiding machine or another multiple lay braiding machine can be realized.

The invention is described below by means of a braiding machine with a single rotor yoke. Again, this is not a limitation.

The invention can also be applied to a braiding machine having a plurality of rotor yokes.

As described above, the strand shaped material is pressed against the inside of the rotor yoke, thereby leading to an increased friction between the moving strand shaped material and the rotor yoke. Thereby, a tensile force acts on the strand shaped material during the guiding along the rotor yoke, which is opposite to the tensile force in the guiding direction, which is generated for example by a rotating winding spool for the braid produced.

The tension generated in this way on the strand shaped material can lead to a quality problem in the braid produced. In particular, if the strand shaped material is a wire, it can be solidified by the load due the tension, and its strain values may worsen. This problem occurs in particular at high rotational speeds of the rotor yoke of the braiding machine.

For solving this problem, the prior art proposed transport devices for the strand shaped material. A transport device in the sense of the present invention should be understood to mean a device, which is arranged at the or on the rotor yoke and which is adapted to contact the strand shaped material and to move at the contact surface with the strand shaped material in the same direction as the strand shaped material. The rollers, which are arranged at the or on the rotor yoke, in particular deflection rollers, or combinations of such rollers are should not be understood as such transport devices.

The WO 2004/011 354 A2 proposes as the transport device a movable conveyor strip driven by a drive mechanism, which moves in front of in the longitudinal direction of the rotor yoke along the path of the strand shaped material, and at a speed that is preferably close to the speed at which the strand shaped material moves on the rotor yoke along its path. The conveyor strip has the form of a circulating endless belt which runs on the inside of the rotor yoke in one direction and on the outside of the rotor yoke in the reverse direction and which is deflected and driven by two deflection rollers spaced at the outer ends of the rotor yoke. By the nearly identical speed of the strand shaped material and the rotor yoke, the sliding friction largely ceases to exist between these two components, and hence the undesirable expansion of the strand shaped material also ceases to exist.

The present invention has the object to provide an improved transport device for a braiding or stranding machine.

This object is achieved by a braiding or stranding machine according to claim 1. Further advantageous embodiments of the invention are the subject of the dependent claims.

The invention is based on a braiding machine for the braiding of a strand shaped material which has a rotor yoke being rotatable around a rotation axis and curved radially outward whose both ends lie on or near the axis of rotation and move along the longitudinal direction of the strand shaped material during the operation of the braiding machine, wherein the rotor yoke has a transport device for the strand shaped material, wherein the transport device is adapted to contact the strand shaped and to move at the contact surface with the strand shaped material in the same direction as the strand shaped material.

The invention is based on the finding that a transport device for the strand shaped material may have a significant air resistance, particularly at higher rotational speeds of the rotor yoke. As the rotor yoke can be configured sufficiently small and/or streamlined by a corresponding profiling in conjunction with a suitable material, it is difficult to achieve the same for the transport device, in particular for their moving parts. However, an increased air resistance of the rotor yoke leads to an increased heating, a greater energy consumption, a higher noise and a stronger vibration excitation of the braiding machine, and therefore it should be avoided.

On the other hand, the loading of the strand shaped material on its path along the curved radially outwardly rotor yoke is not uniform. In fact, in addition to the above mentioned tensile force due to the friction between the strand shaped material and the inside of the rotor yoke, a component of the centrifugal force is added at substantially the second half of the longitudinal extension of the rotor yoke, viewed in the direction of movement. This force component acts on the strand shaped material on its way along the rotor yoke of a radially further outward point to a radially inner point contrary to the direction of the movement. Herby, the elongation of the strand shaped material is reinforced. This effect is the more pronounced the greater the angle is between the tangent of the rotor yoke at a certain point on the rotor yoke and the axis of rotation of the rotor yoke. In contrast, a component of the centrifugal force in the direction of the movement of the strand shaped material acts essentially on the first half of the longitudinal extension of the rotor yoke, viewed in the direction of movement, whereby the elongation of the strand shaped material decreases.

According to the invention, it is therefore provided that the transport device is adapted to contact the strand shaped material on only a part of the longitudinal extension of the rotor yoke. This part is smaller than the entire longitudinal extension of the rotor yoke.

Thus, the contact area between the transport device and the strand shaped material, and thus the expansion of the transport device itself can be preferably limited to a range of the rotor yoke, in which the strand shaped material is used against the effect of the centrifugal force radially inwardly in the direction of the axis of rotation.

Preferably, the transport device is adapted to contact the strand shaped material continuously at least at the second half of the rotor yoke, viewed in the direction of movement of the strand shaped material.

In a region, in which the strand shaped material anyway moves radially outward away from the axis of rotation, and is thereby even supported by the centrifugal force, the transport device is in contrast not absolutely necessary. Such a range is preferably comprised of at least a part of the first half of the rotor yoke, viewed in the direction of the movement of the strand shaped material.

Depending on the structural conditions of the braiding machine, the portion of the longitudinal extension of the rotor yoke can be varied, in which the transporting device contacts the strand shaped material. Here, the specific advantages and disadvantages of the transport device in terms of its aerodynamic drag, its weight, etc. on the one hand and its quality enhancing effect on the stress of the strand shaped material can be weighed against each other on the other hand. Preferably, the transport device is adapted to contact the strand shaped material at 20 to 80%, more preferably at 30 to 70%, even more preferably 40 to 60% of the longitudinal extension of the rotor yoke.

In a further preferred embodiment of the invention, the transport device is adapted to contact the strand shaped material on only one side, in particular on a radially outer side of the strand shaped material. In this way, centrifugal the forces acting on the strand shaped material can be counteracted in a specific way.

In a further preferred embodiment of the invention, the transport device is adapted to contact the strand shaped material on at least two sides, in particular on a radially outer side and on a radially inner side of the strand shaped material. In this way, the strand shaped material can be guided particularly safe, and, for example, a slippage of the strand shaped material from the rotor yoke or the jamming with parts of the transport device can be prevented.

Of course, it is also possible to guide the strand shaped material through eyelets, which are fixed to the rotor yoke, and thereby guide it both in a portion of the rotor yoke, in which the transport device does not contact the strand shaped material, as well as in a portion of the rotor yoke, in the transport device contacts the strand shaped material. In the latter portion of the rotor yoke, the eyelets preferably have a sufficiently large diameter, in order to guide through the eyelets both the strand shaped material as well as the parts of the transport device, which is provided for the contacting of the strand shaped material.

In a further preferred embodiment of the invention, the transport device is adapted such that the parts of the transport device, which are provided for the contacting of the strand shaped material, move during the operation of the braiding machine at substantially the same speed as the strand shaped material. Due to the low relative velocity between these parts of the transport device and the strand shaped material, the strand shaped material may then be guided in a particularly safe manner.

In a further particularly preferred embodiment of the invention, the transport device is a belt conveyor. Here, a belt conveyor should be understood as a device for moving a strand shaped material with a mobile, in particular an endlessly circulating, flat, elongate conveying element, preferably a tape, a belt or a strap. The strand shaped material and the surface of the conveyor element are substantially aligned in parallel, and they are contacting each other so that the strand shaped material is further moved substantially by the friction with the surface of the conveying element. The conveying element of the belt conveyor is preferably deflected at the two outer ends of the belt conveyor by a respective pulley.

In a further preferred embodiment of the invention, the rotor yoke is arranged at the transport device in a closed space, which is filled with a medium having a lower density than the density of the ambient air. This medium is preferably air with a lower pressure than the ambient pressure or a gas with a lower density than air, preferably helium. In the case of air with a pressure lower than the ambient pressure, it is preferably produced by a vacuum pump.

By this medium, the disadvantage of the increased air resistance of the transport device can be in turn, at least partially compensated. In this case, it can be practical to arrange the transport device over a longer portion of the longitudinal extension of the rotor yoke than in an environment of normal air density. The advantages and disadvantages of the transport device on the one hand and the effort to establish a closed space with a medium having a lower density than the density of the ambient air can be weighed against each other in turn in the construction of the braiding machine.

In a further preferred embodiment of the invention, the rotor yoke has a longitudinal extension in that part in which the transport device is adapted to contact the strand shaped material, preferably, only in this part of the rotor yoke, a friction and/or a wear-reducing coating or lining, and in particular a diamond-like carbon coating.

Hereby, the friction between the rotor yoke and the strand shaped material is greatly reduced in this part of the rotor yoke. At the same time, the coating or the lining may be limited to that portion of the rotor yoke, thereby reducing the costs, the complexity of the design, and the weight.

Here, as “a diamond-like carbon”, it is denoted in the usual manner a mixture of spa-hybridized and sp²-hybridized carbon having an amorphous structure which has some of the typical characteristics of a diamond.

The diamond-like carbon shows very good friction reducing properties and wear reducing properties both in an ambient atmosphere as well as in a vacuum or in partial vacuum. This embodiment of the invention can therefore be preferably combined with those embodiments in which the rotor yoke is disposed in a closed space with a medium of lower density, especially air at a lower air pressure.

Further advantageous embodiments of the invention are illustrated in the accompanying, schematic drawings in connection with the following description. It shows:

FIG. 1: a first embodiment of a one-sided transport device according to the invention;

FIG. 2: a second embodiment of a two-sided transport device according to the invention;

FIG. 3: a drive assembly for a transport device according to the invention.

The FIG. 1 shows a transport device 1 according to the invention for a (not shown) radially outwardly rotor yoke bow. The rotor yoke may have side walls adjusted to Coriolis. Along the longitudinal extension of the rotor yoke, a wire 2 is moved in a direction 3.

In the embodiment of the FIG. 1, the one-sided transport device 1 extends along about two thirds of the longitudinal extension of the rotor yoke, namely seen in the direction of the movement 3 of the wire 2, about the end of the first third until the end of the rotor yoke.

On the rotor yoke are supported rotatably a plurality of guiding rollers 5, a deflecting and guiding roller 8, a deflecting and driving roller 7 and a tension roller 6, wherein an endless belt 4 rotates around it along the rotor yoke with about the same speed as the moving speed of the wire 2. The tension roller 6 is mounted transversely to its rotational axis radially inwardly and can be moved outwardly, and can thus be pressed against the endless belt 4 to tension it.

The wire 2 is pressed by the centrifugal force radially from the inside onto the endless belt 4 and it is entrained by it due to the friction. For this purpose, the side of the endless belt 4 contacting the wire 2 may be provided with a friction increasing coating.

The endless belt 4 is a flat, flexible steel strip, and the rollers 5, 6, 7, 8 have smooth surfaces. However, the endless belt 4 may also be a toothed belt and the rollers 5, 6, 7, 8 may be the corresponding toothed belt wheels, in which case then the smooth side facing away from the tooth of the toothed belt is directed to the outside and entrains the wire 2.

The FIG. 2 shows a transport device 1 of the invention, which comprises two separate circumferential endless belts 41, 42. The outer endless belt 41 is guided, as in the embodiment of the FIG. 1, by rollers 5, 6, 7, 8 on the outer side of the wire 2. The inner endless belt 42 is guided in a mirror image to the outer endless belt 41 on the inner side of the wire 2 by means of the corresponding rollers 5, 6, 7, 8.

According to the FIG. 2, the transport device 1 starts, seen in the direction of the movement 3 of the wire 2, just before the half of the rotor yoke. The endless belts 41, 42 move at the same speed in the direction of the movement 3 of the wire 2 and clamp the wire 2 from both sides between them, so that the wire 2 can not move sideways in the transportation device.

For obtaining an accurate guidance of the wire 2 on the endless belt 41 or on the endless belts 41 and 42, respectively, this belt can or theses belts can be provided with a circumferential groove in the longitudinal direction for a receiving of the 2 wire.

The FIG. 3 shows schematically a drive arrangement for a transport device according to the invention. Here, a ring gear 9 is connected coaxially and rigidly with the deflection and driving roller 7. The ring gear 9 meshes with a drive pinion 10, and forms together with it a hypoid gear. The driving pinion 10 is in turn driven via a shaft and two intermeshing bevel gears 11 by a motor 12, which is arranged coaxially to the rotational axis around which the rotor yoke rotates with the transport device 1. Due to the coaxial arrangement of the motor 12 with the axis of rotation, an imbalance due to the relatively large mass of the motor 12 can be avoided to a large extend.

REFERENCE SIGN LIST

1 transport device

2 wire

3 the direction of movement of the wire

4 endless belt

41 physical endless belt

42 inner endless belt

5 guiding roller

6 tension roller

7 deflecting and driving roller

8 deflecting and guiding roller

9 ring gear

10 driving pinion

11 bevel gear

12 motor 

1. A braiding or stranding machine for a braiding or a stranding of a strand shaped material, comprising a rotor yoke being rotatable around a rotation axis and curved radially outward whose both ends lie on or near the rotation axis and move along a longitudinal direction of the strand shaped material during an operation of the braiding or stranding machine, wherein the rotor yoke has a transport device for the strand shaped material, wherein the transport device is adapted to contact the strand shaped material and to move at a contact surface with the strand shaped material in the same direction as the strand shaped material, wherein the transport device is adapted to contact the strand shaped material only on a part of the longitudinal extension of the rotor yoke.
 2. The braiding or stranding machine according to claim 1, wherein the transport device is adapted to contact the strand shaped material at least in a second half of the rotor yoke continuously, wherein the second half is seen in the direction of the movement of the strand shaped material.
 3. The braiding or stranding machine according to claim 1, wherein the transport device is adapted to contact the strand shaped material at 20% to 80% of the longitudinal extension of the rotor yoke.
 4. The braiding or stranding machine according to claim 1, wherein the transport device is adapted to contact the strand shaped material at 30% to 70% of the longitudinal extension of the rotor yoke.
 5. The braiding or stranding machine according to claim 1, wherein the transport device is adapted to contact the strand shaped material 40% to 60% of the longitudinal extension of the rotor yoke.
 6. The braiding or stranding machine according to claim 1, wherein the transport device is adapted to contact the strand shaped material only on one side, in particular on a radially outer side of the strand shaped material.
 7. The braiding or stranding machine according to claim 1, wherein the transport device is adapted to contact the strand shaped material on at least two sides, in particular on a radially outer side and on a radially inner side of the strand shaped material.
 8. The braiding or stranding machine according to claim 1, wherein transport device is adapted to move parts of the transport device which are provided for the contacting of the strand shaped material during the operation of the braiding or stranding machine with substantially the same speed as the strand shaped material.
 9. The braiding or stranding machine according to claim 1, wherein the transport device is a belt conveyor.
 10. The braiding or stranding machine according to claim 1, wherein the rotor yoke is arranged at the transport device in a closed space, which is filled with a medium having a lower density than the density of ambient air.
 11. The braiding or stranding machine according to claim 1, wherein the rotor yoke in a part of its longitudinal extension in which the transport device is not adapted to contact the strand shaped material, preferably only in this part of the rotor yoke comprises a friction reducing coating or lining and/or wear reducing coating or lining, in particular a carbon containing layer such as a diamond-like carbon coating. 